Cylinder lapping tool



J. cs.v M FAEmEfi CYLINDER LAPPI NG TOOL Aug: 11; 1931.

Filed Jan. 25, 1929 2 She ets-Sheet 2 3 taken on'line 33 of Fig. 2,

Patented Aug. 11, 1931 i UNITED STATES PATE oFFIc 'JOHN G.,Jl/ICFADD EN, OF CAMP HOLAIBIRD, MARYLAND CYLINDER LAPPING TOOL Application filed January 25, 1929. Serial No; 334,958.

*5 barrels, etc. a

The primary object of the invention is to providea tool which may be operated by hand or by a suitable prime mover for the purpose of lapping or grinding the interior working surface of a cylinder, or the like, the said tool being effective for removing scratches, scars, or the'like from said working surfaces and for rendering the said cylinder truly circular.

A further object of the invention is to provide a tool of very simple construction; one which may be manufactured at a very nominal cost, and onewhich will be exceedingly effective in operation notwithstanding the simplicity of design.

Other objects and advantages of the inven tion will be apparent during the course of the following description: I

In the accompanying drawings forming a partof this specification and in which like numerals are employed to designate like parts throughout the same,

Figure lis a side elevational view of the lapping or grinding tool embodying this invention, the said tool being illustrated in position within the cylinder, or the like,

Figure 2 is end elevational view looking in the direction of the arrow lines '22 on I Fig. l,

Figure 3 is alongitudinal sectional View Figured is a sectional view similar to Fig. 8 but illustrates the lapping or grindinglsegmerits of the tool retracted for permitting the latter to be positioned within a cylinder, or the likewhich is to'be lapped or ground, Figure 5 is a transverse sectional view taken on line 5-5 of Fig. 4,

Figure 6 is a transverse sectional view of a protectoremployed for shielding the working surfaces of the lapping segments when the tool is not in use, and

' Figure .7 illustrates the protector in position upon the tool.

The device, when briefly described, includes an operating rod or shank A upon which is mounted, in a suitable manner, the lapping or grinding segments B. These segments are intended to be retractedand held in such position while the tool is being inserted into the bore of a' cylinder for the purpose of lapping or grinding the latter. Expanding elements C are employed for yieldably forcing the segments B'into their operative positions in grinding or lappin rela tion; with respect to the working sur ace D of a cylinder, or the like. For the purpose of insuring proper movement of the segments B when being expanded or contracted, guiding elements Eare provided. These elements E also act as driving connections between the segments and the shank A. In certain c linders, it'becomesnecessary,or it'is consi ered advisable, to employ a reduced portion,'such as designated by the character (d), as a guide for the tool during the lapping or grinding 7 operation. To utilize such'reduced portion (d), a guiding sleeve F is slidably associated with the extended end portion (a) of the shankA. y

The above briefdescription is believed to be "sufiicient to convey a general understand ingot the construction and operation of the tool embodying this invention. How.- ever, for the purpose of completely disclosing all of the details of the device, the following specificdescription is given: The'wmus figures are believed to. disclose what is now considered as a preferred embodimentofthe invention, and in this embodiment, the shank A of the tool is formed with a squared-end 10'by' means of which the said shank maybe operatively connected to a brace or other suitable driving means. The said shank preferably is round in section and has secured thereto, at a suitable point within the length of the same, a sleeve 11 One end of the sleeve is provided with an annular groove :12 for re ceiving the edge of a central aperture 13 formed in a washer 14 adapted to be securely and immovably held with respect to the sleeve by having the extremity 15 of the sleeve peene'djor riveted against the fixed washer 1a. The remaining en at the slee e 100 shank A. The guiding elements E perform the additional function of acting as connectors between the sleeve and shank to cause the sleeve to rotate and reciprocate axially with .the shank and to prevent relative movement ofthe sleeve with respect to the shank.

'QAny desired number of segments B may be provided but in the preferredembodiment of the invention, four are illustrated. When expanded, the peripheral surfaces 20 of the segments are intended to *form collectively a true circle which corresponds in diameter with the new or final diameter of the working surface of the cylinder after having been lapped or ground to .the extent desired. Each sector is provided with parallel faces 21 and inwardly convergingfaces 22 which are arranged at'right angles with respect to the faces 21. The faces 22 of adjacent segments are spaced with respect toeach other when the segments are expanded into Working engagement with the interior ofa cylinder.

3 Fig.5 discloses these same faces substantially in contact with each other, which rel- ,ative positioning occurs when the segments are retracted. j

:Each sector .is-provided with an axial socket 23 for receiving an end of a guiding ,element E. I .The sockets 23 are of a suitable length to permit of desired expansion and contraction of the segments relative to their respective guiding elements. Each sector furthermore is provided with a relatively,

large socket 24 arranged in parallelism with the socket 23, as best illustrated in Figs. 3

and 4. The-sockets 24 are each designed to receive a spring 25 which bears at one end against the sleeve 11 "and at its other end against the closed endof the socket 24. It will be noted, by examining Fig. 5, that the springs for diametricallyopposite segments are arranged in axial alignment with respect tothe guiding element for the remaining two segments but are positioned in the same plane with said elemen s One face 21 of each segment slidably engages the fixedwasher 14. An adjustable washer'26 encircles the sleeve 11 and bears against the remaining face 21 of each 'of the bore portions, such as designated by the character (cl). When such cylinders are to be lapped or ground, a guiding element F is employed and takes the form of a sleeve having a tapered outer face 28 and a bore 29. The guide may be driven into the reduced bore portion (03) from the exterior of the cylinder for frictionally holding the guide with respect to the cylinder. The extension or outer end portion (a) of the shank A is slidably positioned within the bore 29 of the guide.

For the purpose of preventing the highly polished and perfectly tooled peripheral surfaces 20 of the segments from becoming scarred or damagedwhile the tool is not in use, a soft flexible band 30 is provided. This band may be made of any desired material, such as leather, rubber, or even soft metal. The band 30 may be of a proper size to encircle the segments G when in their expanded or contracted condition. Fig. 7 discloses the band encircling the segments while the latter are expanded. I 1

The operation of this lapping or grinding tool may be described as follows: The cylinder to be lapped or ground is arranged in an accessible manner with respect tothe person intending to operate the tool. The segments B then should be compressed or moved inwardly into the position illustrated in Fig. 5. The nut 27 then should be threaded along the sleeve 11 for forcing the washer 26 into tight engagement with all of the segments whereby the latter will be securely held between the two washers 14 and 26. After so conditioning the tool, a suitable lapping or grinding compound should be placed or'spread upon the peripheral surfaces 20 of the segments. The tool then should be positioned with respect to the cylinder so that the segments are arranged withinthe bore of the cylinder and adjacent one end of the latter, or as best illustrated in Fig. 4. After so positioning the tool, the nut 27 should be adjusted upon the sleeve 11 for releasingits pressure upon the washer 26 whereupon the springs 25 willexpand'the'segm'ents to place their working surfaces 20, with the superimposed: lapping 'or grinding compound, in engagement with the bore D'of the cylinder. By then reciproeating or oscillating the shankAwith respect to the cylinden the desired lapping operation will beaccomplished. This action should continue'until the interior working surface of the cylinder has reached'the desired degree of'pe-rfection. f

It is to be understood that the form ofthis invention herewith shown and described is to betaken as a preferred. 'exampleof the same, and that various changes in the'shape, size, and arrangement of parts maybe' resorted to without'departing from the spirit of the invention or the scope of the subjoined claims.

Having thus described the invention, I claim:

1. A tool of the type described comprising a shank, a sleeve positioned upon the shank, radially extending guiding pins offset in angular relation to each other passing through the sleeve and the shank, a stationary washer secured to the sleeve, a second washer adj ustable axially of the sleeve, segmental sections positioned between said washers and guided by said pins, means for yieldably forcing the segments radially of said shank, and means for moving the washers toward each other to retain the segments in any desired adjusted position.

2. A tool of the class described comprising a shank, a sleeve positioned upon the shank, radially extending guide pins ofl'set in angular relation to each other passing through said sleeve and shank, a stationary washer secured to said sleeve, a second washer adjustable axially of said sleeve, a plurality of interchangeable segments positioned between the washers and guided by said pins, means for yieldably forcing the segments radially of said shank, and means for moving the Washers toward each other to retain the segments in any desired adjusted position with respect to the shank.

3. A tool of the class described comprising a shank, radially extending guide pins offset in angular relation to each other and passing through the shank, a stationary washer secured to the shank, a second Washer adustable axially of the shank, a plurality of inte-rchangeable segments positioned between the washers and guided by said pins, a plurality of compression springs seated in suitable openings in the segments for forcing said segments radially of the shank, and means for moving the washers toward each other to retain the segments in any desired adjusted position with respect to the shank.

In testimony whereof, I have hereunto set my signature.

JOHN G. MCFADDEN. 

